1. Field of Invention
The present invention relates generally to fluid transfer between a ship and a second location. Specifically, the present invention provides a mobile transfer system with hoses in pair being pulled out simultaneously from a reel to form a fluid path. During non-transfer periods, hoses are wound up around the reel for storage.
2. Description of the Related Art
Floating production has been widely used for processing and storing hydrocarbon fluids on a vessel that is stationed near a field. A tanker is used to transport the fluids to terminals near users. In this case, a loading system is needed to transfer the fluids from a production vessel to a tanker. In other cases, fluids need to be transferred from a service vessel to a drilling vessel, from a fuel barge to a ship, from a large vessel to a small vessel (lightering), between an onshore facility and a ship, from a suction vessel to shore in hydraulic dredge, etc. In a benign environment, a vessel is moored to another vessel or dolphins side by side. Fluids are transferred through the middle-ship manifolds with either air hoses (i.e., hoses suspended in air) or hard arms. To enhance safety, a certain distance (e.g., 60 to 120 m) is needed especially for vessels docked in a harsh environment. One way is to dock two vessels in a tandem configuration. Another way is to install a floating buoy moored at a single-point (SPM) with a turntable on top. The buoy is stationed at a distance from a production vessel, a tanker is moored to the buoy with a hawser. In both ways, the tanker can re-orientate automatically in alignment with a wind/current direction.
As an alternative to ports, a SPM buoy has been used in shallow water for fluid transfer between a tanker and an onshore facility with a riser and a subsea pipeline extending from the buoy to shore. A buoy (e.g., floating cans) has also been used for fluid transfer between wells and a FPSO where a riser extends from the buoy to the wells. When used for deepwater field development, a buoy can be located at a few hundreds meters under the sea surface and hold a riser below with buoyancy.
Floating hoses are also used for fluid transfer between a stationary vessel and tanker or between a SPM buoy and tanker. A current practice is supporting a reel/wheel on a stationary vessel or station, and pulling one end of hose from the reel over to a tanker. After fluid transfer, the hose is reeled back to the reel. This system requires a swivel joint at a reel axle between the rotating reel and fixed piping on the station. When a SPM buoy is used, a hose is freely floating in water. A floating hose left in water is subjected to potential damage caused by a third party or storms. Alternatively, the hose can be wound around a reel that is rotatable to its base anchored to the seabed as disclosed in U.S. Pat. No. 7,438,617 to Poldervaart et al., but this requires significant changes to an existing SPM buoy. Alternatively, U.S. Pat. No. 7,836,840 to Ehrhardt et al discloses a submersible turret that is connected to a socket at a ship bottom. The drawback of this system is the need for significant changes to existing tankers.
In order to save space on a production vessel, many solutions have been proposed. For example, US application No. 2013/0240085 to Hallot et al discloses multiple reels stocked up on top of each other aboard a production vessel, and floating hoses are wound around the reels after fluid transfer. U.S. Pat. No. 8,286,678 to Adkins et al discloses a transfer vessel with submerged conduits freely hung between a production vessel and the transfer vessel. U.S. Pat. No. 6,427,617 to Breivik et al discloses a floating hose with a swivel at one end and the hose is stored above water along a hull side. U.S. Pat. No. 5,803,779 to Horton discloses a transfer system having two reels on a buoy along with two swivel joints and three hoses. That is, one hose extends from one reel to a production vessel, another hose extends from the other reel to a tanker, and a third hose (or conduit) is used for fluid connection between two axles of reels. All these systems require swivel joints.
Therefore it is desirable to have a universal transfer system without swivel joints for fluid transfer between a ship and a second location (including a station) separated at a wide range of distances.